Field of the Disclosure
The invention relates to fluid separation systems and methods. More particularly, the invention relates to systems employing spinning membranes for fluid separation and methods for operating such systems.
Description of Related Art
Various blood processing systems now make it possible to collect particular blood constituents, instead of whole blood, from a blood source such as, but not limited to, a container of previously collected blood or other living or non-living source. Typically, in such systems, whole blood is drawn from a blood source, a particular blood component or constituent is separated, removed, and collected, and the remaining blood constituents are returned to the blood source. Removing only particular constituents is advantageous when the blood source is a human donor, because potentially less time is needed for the donor's body to return to pre-donation levels, and donations can be made at more frequent intervals than when whole blood is collected. This increases the overall supply of blood constituents, such as plasma and platelets, made available for transfer and/or therapeutic treatment.
Whole blood is typically separated into its constituents (e.g., red cells, platelets, and plasma) through centrifugation, such as in the AMICUS® separator from Fenwal, Inc. of Lake Zurich, Ill., or other centrifugal separation devices, or a spinning membrane-type separator, such as the AUTOPHERESIS-C® and AURORA® devices from Fenwal, Inc. Such separation devices typically comprise a fluid circuit having a separation chamber, sources or containers of various solutions, and collection containers that are interconnected by tubing and which is mounted onto a durable hardware component that includes pumps, clamps, and sensors that are automatically operated by a programmable controller to perform the desired blood separation procedure.
Operation of the system to perform the desired procedure requires control of the fluid flow rates and volumes of fluid circulated through the various components of the fluid circuit. Fluid flow through the fluid circuit is caused by operation of the pumps acting on the tubing segments associated therewith. Flow rates through the tubings caused by the pumps may vary from procedure to procedure, and even during the course of a single procedure, due to factors such as variations in the tubing comprising the fluid circuit, changes in inlet pressure, variations in how the fluid circuit is mounted to the durable hardware component, variations in the characteristics of the biological fluid being processed (such as variations in hematocrit), etc. Given the potential for variation in flow rates and volumes, it is necessary to monitor and, if necessary, adjust the operation of the pumps to insure that the separation procedure is safely and efficiently performed. By way of the present disclosure, systems and methods for calibrating pump stroke volumes during a blood separation procedure are provided.